John deere 318 keeps throwing belt

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My 318 keeps throwing the deck drive belt. It seams to do it every time I get into taller grass. I just bought a new belt yesterday and it threw after a few passes. The old belt was a month old. I pulled the deck and checked all the bearings and they are good. The bearings in the idlers on the mule drive are good. The only slight issue is that the shives and idlers are getting worn but they have been that worn for a long time.

I thought the issue was the load my gator blades were putting on it but I have them before till the belt was bottomed out in the shives and had no more adjustment. I put my regular blades back on and it still does it.

I used to never have this problem even when I was hogging through grass till the belt slipped.

What am I missing here? My next step is to replace the shives and idlers. The mule drive is getting sloppy but I will buy a new mower before I replace that. Deeres belts are made in China now and seam to be stretching faster also.
 
Isn't there a spring that keeps tension on the belt by pulling the deck to the rear? If so, is it in place and functioning properly?
 
No. The mule drive has the belt tension mechanism in it. At first I thought that it kept loosening up but the adjustment is staying where I put it. This mower has a horizontal shaft engine and the drive belt curls up to the clutch on the front of the engine. This set up is hard on belts to begin with.

This mower is still a good mower and I got it for free except for all the little stuff that keeps breaking. I love the lever operated hydro. I am torn between getting a new deck and seat and running this till it dies or buying a new mower. I work for john deere so I get a discount on new mowers...really tempting.
 
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That 318 is a solid tractor. It would be pretty difficult to find something new that is built as well as that one. Does yours have power steering?

As for the belt, don't buy Deere belts. I stopped buying them a few years ago due to the stretching problem. I've had much better luck with the blue kevlar Huskee belts from tractor supply.

If your idlers are worn that could be a major cause of it throwing the belt, especially if it does it under load. My G110 had the same problem, and it ended up being a severely worn idler pulley. I replaced the pulley and it has been fine since. Mine has the powerflo bagger fan that is driven by the deck belt, so I guess that puts a little extra strain on everything.
 
So this is the belt from PTO to deck? or the belt on the deck itself?

There's got to be a bent sheave, pulleys out of alignment or a pulley not spinning properly for this to happen.

Like said, this is a solid setup, where belts should last a very long time. I've had a few setups like this over the years.
 
Yeah it has power steering. Deere does make a mower that is built as good as the 318 but it would cost me over 10 grand even with my rebate.

I am thinking of finding somewhere else to get belts from. The problem is that the belt is an odd size and twists. The twisting is hard on belts to begin with.
 
Originally Posted By: JTK
So this is the belt from PTO to deck? or the belt on the deck itself?

There's got to be a bent sheave, pulleys out of alignment or a pulley not spinning properly for this to happen.

Like said, this is a solid setup, where belts should last a very long time. I've had a few setups like this over the years.


It is the belt from the engine to the deck. There isn't any alignment cause the belt twists up to the clutch. Nothing is bent.


95 bucks for the jack sheave. 23 for the idlers. Pto sheave is attached to the clutch and that unit is 450.

Or 1800 for a new deck and mule drive...
 
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is it an oem belt?

OEM JD belts are wierd sizes example 11/16, and 9/16

most aftermarket are 5/8 or 1/2"

I've had numerous problems with non-oem belts blowing on the JD316 and 318


so dont get that STENS "exceeds oem" belt etc.
 
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I've had a few Deere's and the last one was a 318. WONDERFUL tractor, probably among the best small tractors ever made. One thing to look for is ANY small mark on the edge of one of the pulleys. This usually happens when the belt is thrown off the first time and then it just acts as a "jumping off point" from then on. I had a 214 that got the tiniest notch in the drive pulley on the rear end and every time that tractor was used to pull a heavy load, or got under any kind of heavy load, then it would kick that belt off. Regular mowing wouldn't do it. Tried to repair/polish out the nick, to no avail. Replaced the pulley and the problem was gone. If I were you, I'd scrutinize every pulley to see if one has a slight notch, dent, bend or whatever and replace it.
I've used both JD belts and aftermarket belts on mine and never noticed any real difference except in my wallet, but since you're having problems, I think it would be a good idea to buy original belts and eliminate that one variable.
 
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Ok I think I have come to the 400 dollar conclusion. My mule drive is worn out. I pulled everything apart on the deck and pulled the clutch apart to check the bearings and adjust it and found nothing wrong. I put it all back together and stated it up and got down and watched it while running. The belt returning to the deck is flopping wildly as is the arm on the mule drive that holds the return side idler.

All the parts that are worn out will cost me just as much and a whole brand new mule drive on ebay. If I bought the mule drive from john deere it would be 100 bucks more than ebay. And I am still not 100% certain that this is going to fix it.

This mower has a lot of life left in it as it only has 860 hours on it. There are a lot out there for sale that have twice that amount of hours on it and still run. My 1 acre yard isn't going to wear it out anytime soon.
 
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Sounds like a keeper !

Belts do flop quite a bit so what you're seeing may be normal , I can't say without seeing it .

Why did you replace the old belt ? As someone mentioned if you have a pully that has a groove worn in it that will make the belt climb out and this usually always becomes an issue when you put on a new belt because it isn't glazed and it is a wider V so it really grips the pully surfaces .

You mention you work at a JD dealer ? , why not let one of the Tech's have a look ?
 
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The belt flopping and the idler arm flopping is what got me to thinking it the the mule drives fault. When the mower is pulling harder like when the gator blades were on or in heavy grass or bouncy terrain it is going to slack the belt more on the return side. It is already at a bad angle because of the deck being pitched down. There isn't anything you can do much about the angle because of how this operates.

I replaces the last belt because it did this same thing. This current belt lasted two passes before it threw it. The old one lasted a month and was thrown at leased once per mowing for the last few weeks. The one before that was over two years old but started getting thrown. Usually once the belt is thrown they won't say on after that.

I don't work for a deere dealer. I work at a deere plant where they make the balers and self propelled windrowers. If I had some more time in and got to know some people I could probably have our expiramental shop find the parts in the system and have them made at our plant.
 
I would strongly suggest you have a knowledgable person look at this for you before you start switching out parts .
There is no way I can even begin to diagnose what it might be from the info nor would I be able without seeing it and looking things over .

You have a great mower there and chances are it's something simple (lets hope so ) so get it looked at if you aren't sure is the best advice I can give from here .

You might try a JD forum , there are guys on there that know the 318 inside out .
)
 
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The best John Deere garden tractor forum is
www.weekendfreedommachines.com

If you have not already done so, take off the belt and spin every pulley by hand and feel and listen to how they turn.
I have had pulleys with bad bearings that spun roughly and would catch at high speeds and throw a belt.
 
Originally Posted By: cronk
The best John Deere garden tractor forum is
www.weekendfreedommachines.com


I can't figure that site out. It is weird.

I looked everything over again and found nothing wrong or different. I tightened the tension way up and it stayed on long enough to finish the yard. It is way tighter than I have ever had to adjust it to the point where I don't want to lift the deck.

I am going to pull the front of the deck up more to help this but there isn't much adjustment left.
 
Originally Posted By: jhellwig
Originally Posted By: cronk
The best John Deere garden tractor forum is
www.weekendfreedommachines.com


I can't figure that site out. It is weird.

I looked everything over again and found nothing wrong or different. I tightened the tension way up and it stayed on long enough to finish the yard. It is way tighter than I have ever had to adjust it to the point where I don't want to lift the deck.

I am going to pull the front of the deck up more to help this but there isn't much adjustment left.



Yeah that site is a little confusing.

Try My Tractor Forum, they are very helpful and friendly.

Here is the John Deere garden tractor section:

http://www.mytractorforum.com/forumdisplay.php?f=12

thumbsup2.gif
 
Originally Posted By: jhellwig
Originally Posted By: cronk
The best John Deere garden tractor forum is
www.weekendfreedommachines.com


I can't figure that site out. It is weird.



It's not overly complicated, they use older forum software.
For your tractor, click forums, then go to "restoration and repair forum", then click "hydrostatic drive tractors"

That is the place to ask your question. A lot of knowledgeable JD tractor owners there, I'm sure someone knows what your issue is. I just got a 316 so I'm learning!
 
Originally Posted By: jeepman3071
As for the belt, don't buy Deere belts. I stopped buying them a few years ago due to the stretching problem.


I've always been told the exact opposite. Deere OEM belts seem to solve a lot of issues caused by "will fit" belts. I can't argue with your experience though, just an observation.

Weekend Freedom Machines is definitly a site with a ton of knowledege on it. You have to make it past the klunky forum interface. You also have to realize that it's for information exchange only. It's not a social forum, and the moderators don't have much in the way of a sense of humor. Definitly a good resource, if you can get past all that.

I prefer My Tractor Forum. There's a lot of knowledge there too, and a much more relaxed atmosphere.
 
I use to use a 5/8" belt on my PTO to deck belt on my JD F510. The deck belt I used a 1/2". Neither were the JD OEM size which is not available from anywhere but JD. The 5/8" belt made the blades spin faster.

But the larger than OEM PTO belt eventually wore out the pulley on the PTO and the shieve. Replaced both last year. I kept the 1/2" deck belt and went to a 1/2" PTO belt. It slowed the balde speed down a bit but I can live with it.
 
Originally Posted By: SHOZ
The 5/8" belt made the blades spin faster.


How exactly does that work?
 
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